First, fill something to the nick of overfilling. It doesn't matter what it is: a bag almost bursting with stuff; an ominously creaking cliff; an elevator nearing its maximum occupancy; a morbidly obese gourmand's stuffed stomach; you name it. When you've finished, add just a teeny, tiny bit more. Watch your recipient blow/crack/shatter instantly and/or loudly.

Basically, a literal interpretation of "the last straw that broke the camel's back".

This trope applies to situations where maximal capacity is reached, and even an infinitesimal quantity surpassing it causes effects far more massive than common sense could predict.

Although the most common variation of this is when a group of people/stuff is at a ledge and a light feather/dust powder lands and it simply breaks apart instantly (and painfully), it's not only restricted to those cases.

Examples:

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Advertising

The US commercial for Super Mario World 2: Yoshi's Island is similar to the scene from The Meaning of Life, with a man eating a huge amount of food to represent everything that was crammed into the game. When he's full, he has a bit of whipped cream or something (to represent a bonus level) and ... kablooie. Which soon got censored after it first aired. In the original versions of it the dude is seen exploding. Censored versions had him exploding off screen.

A 90's commercial for a car had a man on a step ladder pouring soda into a very fragile bucket to represent the amount of gasoline needed to power other brand cars. He continuously pours more soda in to represent every stop he makes to get gas. When the bucket is about to overflow, the narrator tells him to get some gas "for the trip back home". Guess what happens next?

Two Australian men have loaded a pick-up truck to capacity with Castlemaine XXXX beer. They add a couple of bottles of sherry for the ladies, and the truck's groaning suspension finally collapses. Of course, they conclude it was too much sherry.

In an Allstate insurance ad, the "mayhem" pitchman is lying on a garage roof in winter, representing a growing load of snow. At the end, he blows air at a snowy tree branch, causing a few ounces of snow to fall on him and the roof to immediately collapse under the additional weight.

Comic Books

In Carl Barks' Donald Duck comics story "A Christmas For Shacktown", Scrooge's money bin has become so full that when he drops in just one more dime, the ground under the bin caves in and all of his money falls into a deep pit with a thin floor—right over a lake of lava. We don't find out how he got it all out until Don Rosa's story "Gyro's First Invention".

An issue of The Batman Adventures has Mastermind, Mr. Nice, and The Professor escaping from Gotham City State Penitentiary ridiculously easily. As Mastermind and Nice try to think of some way to create a diversion in the cafeteria (which is at the moment occupied by hundreds of violent, sociopathic, could-snap-at-any-moment hardened criminals having dinner), the Professor simply stands up, clears his throat, and calmly announces: "Fire." All the convicts panic, the guards (thinking they're trying to start a riot) retaliate, and then a real riot breaks out, during which the trio slip away unnoticed.

Comic Strips

FoxTrot did a variation as a Shout-Out to the former Trope Namer, with Peter and Paige's heads bloated from an all-night cram session (and a viewing of Meaning of Life) and Jason offering them "onlee a wafer-theen formula".

Garfield: Happens in a strip◊ with a Christmas tree toppling from the addition of one last decoration (pictured above).

Eastern Animation

In one of the episodes of Nu, Pogodi!, the Wolf has barely managed to lift a very heavy barbell, when a butterfly lands on it, with predictable results.

Films — Animation

In The Boxtrolls, Snatcher is already bloated from falling in the remains of the Briehemoth. Eating one more piece of cheese causes him to explode.

Stitch of Lilo & Stitch can lift three thousand times his own weight, but collapses under even a little bit more.

In Stitch! The Movie, Hamsterviel restrains Stitch with his weight "times three thousand and one!"

Race for Your Life, Charlie Brown: Snoopy and Woodstock get lost in the woods at night and slip down a cliff. Snoopy manages to save himself by grabbing a hold of a tire hanging from a branch. When Woodstock perches on the tire, their combined weight causes it to fall.

Films — Live-Action

Monty Python's The Meaning of Life has the infamous sketch where Mr. Creosote eats exorbitant amounts of food while vomiting profusely. The Maitre d' then approaches him with a wafer-thin mint — the former Trope Namer. After a few rude protestations that he was full, Mr. Creosote was coaxed into eating the mint. The Maitre d' then finds a hiding spot as most of Mr. Creosote's body explodes into chunks of innards and bile.

In True Lies the bad guys' truck is hanging off the edge of the bridge and they sigh in relief that it didn't go over. Then a pelican lands on it...

James Bond movie For Your Eyes Only: Car with baddie who killed Bond's buddy is poised on edge of cliff; Bond walks up and tosses (the baddie's own calling card) a pin at the car. Expected results, but the car doesn't fall. In a subversion of sorts, Bond gives the car a kick for good measure.

In Beetlejuice, Adam and Barbara are driving over a covered bridge and swerve to avoid a dog. They crash through the wall of the bridge and end up poised on the edge, teetering above a river. They look back and see the dog standing on a broken plank, panting happily at them. The dog hops off the plank, and over they go.

In Black Sheep (1996), a huge boulder behind the cabin in which the two main characters are staying is loosened by, among other things, David Spade's character standing on it and a rodent digging under it. Finally, a bird flying overhead poops on it, and...

Spy Hard: In a flashback, Steele makes a false presidential rescue thinking there's a threat. He ends up having his feet hanging over the ledge of a bridge along with the president's car. He stretched his arms out with his wallet to keep himself from falling.

In the film of Wizards of Waverly Place Justin has to make a bridge. He's very proud of it and taunts Alex until she wordlessly takes a pebble and tosses it on the bridge. The Genre Savvy can guess what happens.

Road Trip: Seann Scott's character demonstrates he can spit across a ten-foot wide broken bridge. He did, but causing the other end of the bridge to collapse from his spit.

In The Hobbit: An Unexpected Journey, Bombur is sitting on a bench that's audibly creaking under his weight. So one of the other dwarves decides to toss him a sausage, and the bench promptly collapses.

At the beginning of Cas and Dylan, Dr. Cas Pepper is already a widower and facing a fatal, inoperable brain tumor. When his beloved dog unexpectedly drops dead during an innocent game of fetch, Cas sets out on a cross-country trip to (a) give the dog a proper burial and (b) end his life on his own terms.

Literature

In the Discworld book Interesting Times, Rincewind is dangling above a giant fall, barely supported by a few rotting logs. A quantum butterfly lands on his hat, and, wary of this exact trope, Rincewind tries to blow it off - so it starts making it rain just over his head, which is enough to drop him. It also stings him with a very small lightning bolt.

The children's book The Mitten is about a small boy's mitten that gets dropped in the woods. First a little mouse finds the mitten and finds it a cozy nest. Then along comes a small frog, and then a rabbit, and the mitten is pretty much big enough for them, and quite warm. Then things start to get out of hand when a fox, then a wolf, and then a bear arrive and clamber for space in the mitten. Finally a doddering granny grasshopper comes along and blows off their cries of "No room! No room!" by saying, "There's always room for one more!" She nudges in one foot and the mitten goes plooie.

In the Jan Brett version, the animals start with rabbit, and the mitten doesn't explode until a mouse snuggles herself on the bear's nose.

Similarly, in the picture book "Who Sank the Boat", every time an animal gets in we're asked "Do you know who sank the boat?" The answer, of course, isn't one of the big animals but the little mouse, the last to get in, the smallest of all.

The Annie M.G. Schmidt poem De brug bij Breukelen (The Bridge Near Breukelen) has everyone and everything going over a bridge safely, until a mosquito lands on it...

In Horton Hears a Who! and its adaptations, the microscopic Whos live on a speck of dust, and the only normal-sized animal who can hear them is an elephant named Horton (due to his large ears). The other animals get sick of Horton talking about the Whos and plan to boil the dust speck in oil, so the Whos all try to make as much noise as possible to prove their existence. Finally, the Mayor finds one Who who isn't contributing—a particularly small Who named JoJo (his son in some adaptations)—takes him to the highest point in town and has him make a loud "YOPP!" This added to all the other Whos' noises finally allows the animals to hear them, saving the town.

Live-Action TV

8 Simple Rules: CJ stands on the trap door to the attic, holding a bowling ball and a teddy bear. He drops the bowling ball so the trap door would go up. Nothing happens. He drops the teddy bear, and then the trap door goes up.

In the iCarly episode "iDate a Bad Boy" Spencer buys a pressure sensitive alarm in front of the door to prevent Carly from sneaking out. Carly jumps up and down on it, and it doesn't go off. Later, an obese postman comes to give a package to Spencer, telling him that it needed one more stamp. The postman steps on the sensor with the package. Nothing. Spencer gives him the stamp to complete the postage, and then alarm goes off.

Seinfeld: George's wallet. The "mint" is a phone tab from an ad (a strip of paper just big enough to fit a phone number).

House: Played with; the team has to diagnose a morbidly obese man in a coma. They eventually get to the point that they need to get an MRI. Only problem? The weight limit for the MRI is 450. The man in question weighs over 600.

Cameron: The weight limit's obviously just an estimation. It's not like it can hold 450 pounds fine and then collapse under 451. Chase: He's not 1 pound over, he's 150 pounds over.

Surprisingly, the MRI machine holds until the patient wakes up, whereupon he promptly breaks it via struggling to get out.

The MythBusters have tested the "bird landing on a car making it fall" scenario. (Busted, twice over.)

A variation appears on Frasier; a sleep deprived Niles misses out on the last stirring straw at Cafe Nervosa, and promptly has a breakdown, stripping naked and thinking he's still dreaming.

Pro Wrestling

According to World Wrestling Entertainment, the rings used for (among other things) the massive Royal Rumble Match held every January can bear the weight of approximately five non-metric tons, or 10,000 pounds - enough to bear the weight of about 40 standard-sized male wrestlers (the average male WWE Superstar weighing about 250 pounds). But if even a cruiserweight (wrestler weighing less than 200 pounds) jumped in after them, the whole thing would presumably collapse. Fortunately, 40 is the absolute maximum number of Superstars ever allowed in the Royal Rumble Match over its two-and-a-half decades of existence, and no more than 15 of those guys at the most are ever in the ring all at once (the overwhelming majority of the contestants being unable to stay in the match for 60 minutes, which is the average length of a Royal Rumble), so the chances of such a thing happening are practically nonexistent. When a superheavyweight (400 pounds or more) performs a top-rope maneuver on another superheavyweight, however...

Video Games

In NetHack, once you've eaten enough to become satiated, eating (almost) anything will give you a warning. If you keep trying, you may choke to death. This includes the corpses left by wraiths, which are incorporeal. Note that it's only possible to survive if you're wearing an amulet of magical breathing. This is referenced on "Lessons Learned the Hard Way": "Don't eat wraith corpses when satiated. You don't get a warning."

In The The Elder Scrolls IV: Oblivion, you can run at full speed while being 0.1 weight units under your limit and preform stunning feats of acrobatics if your level is high enough, but if, in that state, you get hit by a 0.1 weight arrow, you are instantly immobilized.

While not quite the same thing, in Breath of Fire IV the God-EmperorFou-Lu has spent the entire game with a target on his head by the very empire that resurrected him. Near the end of the game, they decide to go all out and drop a Fantastic Nuke on him. He survives this, only to notice the hair accessory of his love interest near him. They'd used her for ammo. This act effectively convinces him to go from Humans Are Bastards but he can live with it to Kill 'em All and then burn the world down.

In God Hand, when a demonic enemy is both down to their last bit of health and stunned, a prompt appears for "Poke of God", which causes Gene to finish the enemy with a light poke.

It's possible to drain the patient's blood level in Surgeon Simulator 2013 to an incredibly minuscule amount via whichever tools you decide to use, then finish him off with something seemingly inconsequential. This happens in an Achievement HunterRage Quit video; the patient is stabilized at 1 mL of blood (out of 5600), then is killed by a jab from a syringe.

Ghostbusters: The Video Game: In the Realistic version, this is how the tutorial ghost—the Sloth Ghost—died. In life, he was an obese, extremely wealthy, and very lonely gourmand who won a huge Thanksgiving feast, which he ate single-handedly...with decidedly lethal consequences. This was how he chose to die.

Web Comics

In The Inexplicable Adventures of Bob!, Galatea is eating at a posh French restaurant and making her usual complete pig of herself. In a shout out to Monty Python, it turns out the long-suffering waiter fed her The Wafer Thin Mint some time ago, to no effect, and she orders another plate-full of them, just to emphasize what a bottomless pit her stomach truly is. After the meal, she skips out on the check.

Variant. Hannelore's father owns a space station with its own AI, which controls the environment, life support, holograms, geosynchronous thrusters, and coordinates flights, EVAs and the crew. Hannerlore's father uses a MP3 player unconnected to the system for his music, since he doesn't feel it's a good idea to have the AI do everything.

Faye has a long history of behavior at her job at Dora's cafe that most other employers wouldn't tolerate for an instant, but Dora lets slide to one extent or another due to their friendship. It's catching Faye drinking on the job that finally pushes Dora past the point of tolerance, and she fires Faye immediately.

"Frigid Hare": Bugs and the big bad Eskimo are hanging onto a broken off ledge that is literally swinging in the wind. The penguin looks down at them, accidentally dislodging a single snowflake which drifts down onto the ledge...

The classic Goofy bodybuilding sketch in Goofy Gymnastics. He's holding up a weight that he can barely hold. A fly lands on one end, he starts to tumble, but stays up. The fly walks across the barbell, and at that time he falls through the floor.

Bugs Bunny sets it up in Little Red Riding Rabbit, by piling a bunch of goods on top of the big bad wolf, who's straddled right over a bunch of hot coals, but just as he's climbing up a ladder to invoke the trope with a feather... LRRH shows up. Red is, in this case, a Genre (or at least Story) Savvy teenager with a loud, obnoxious voice and a fairly clear idea of how things go. She's been spending the entire short harassing Bugs and the wolf ("Hey Grandmaaaaa!"), and her barging in while Bugs is busy is a Wafer Thin Mint all on its own. Bugs abandons his attempt to roast the wolf in favor of leaving Red at the bottom of the pile, while standing off to one side sharing a carrot with the wolf! That seems a bit harsh, even for Red.

Bugs: I'll do it, but I'll probably hate myself in the morning.

This gag happened frequently on both Tiny Toon Adventures and Animaniacs, possibly in reference to its frequent use in Looney Tunes. In one of many examples from Tiny Toons, Babs adds "I just can't help myself" as she delicately places a single rose on top of a gigantic pile someone is carrying. Guess what happens.

Used to great effect in the episode "Mr. Plow", when a vehicle is peering off the edge of a road, about to topple in sideways. The saving gesture? Turning the radio dial to the left, causing the vehicle to flop back onto the road.

Bart gets sent to military school in "The Secret War of Lisa Simpson" as punishment for pulling a literally disastrous prank at the police station while he and his class were on a field trip there. The prank involved stealing every bullhorn in the station and lining them up end to end, creating a mega-mega-mega-megaphone the length of an entire room. A fly buzzes right past the speaker of the bullhorn nearest Bart's mouth, creating an ominous rumble that sounds like a distant earthquake. Ignoring this, Bart puts his lips right up to the speaker and softly says, "Testing..." - and the result is a sonic shockwave that ripples across all of Springfield and levels half the town atomic-bomb style!

In "Bart Sells His Soul", Moe opens a family restaurant called Uncle Moe's Family Feedbag. Not wanting to hire any waiters or waitresses, Moe takes all the orders himself, causing himself to become extremely stressed out and slowly go to pieces as the customers' demanding, insensitive, and sometimes rude behavior get the better of Moe. Krusty notices a throbbing vein of rage building up on Moe's forehead and points it out to the other diners, saying, "That guy's gonna blow." Sure enough, Moe finally reaches his breaking point when a sickeningly cute little girl calls out to him that "My sodie's too cold. My teef hurt." Moe explodes in a colossal temper tantrum: "Aww, your 'teef' hurt? WELL, THAT'S JUST TOO FREAKIN' BAD! I CAN TELL YOU WHERE TO PUT YOUR FREAKIN' 'SODIE', TOO!" The little girl starts crying, the customers all react with outrage at Moe's Cluster F-Bomb, and everyone files out of the restaurant as Moe desperately tries to apologize.

In "Hurricane Neddy", Ned Flanders' home gets destroyed by a hurricane, and Homer leads Springfielders in rebuilding it. But as Ned is touring it, he finds it's shoddily built (e.g. painted dirt rather than floorboards). But afterwards, Homer asks "What do you think of the house love built?", lightly patting it and having it completely collapse.

In "The PTA Disbands", the school's previous bus is shown sitting abandoned in a lot. When a leaf falls on it, it explodes.

An animated segment on Sesame Street featured an elevator where first the operator, a fairy, soldier, witch, kangaroo, taxicab, fireman, clown, gorilla, and a mouse get on board. (The point of the sketch is to teach children how to count to ten.) When the mouse gets on board, the elevator shakes and then explodes, sending the operator falling to the bottom of the shaft.

Another example: a kid yanks the bottom can of a stack and the whole store collapses.

This was dramatically demonstrated in one scene in an episode of Lilo & Stitch: The Series where Stitch is lifting ten girders and two bulldozers. Gantu comments, "You can lift three thousand times your own weight and not an ounce more." He then proceeds to throw his backstage pass on the pile, causing a total collapse.

Gone Nutty, a short starring Scrat from Ice Age: Scrat has filled a log full of acorns and is just putting in the last one. But the log is so full that that last acorn keeps popping out. In trying to push it back in, the bottom collapses, sending all the nuts - and Scrat - tumbling down a cliff.

One episode of DuckTales (1987) has the Beagle Boys mounting a full-scale offensive on Scrooge McDuck's Money Bin. Bigtime Beagle shows up wearing a full suit of armor; Scrooge shows up driving a tank. Bigtime crows that his armor can withstand a 60mm shell; Scrooge responds by saying that his tank fires 61mm shells, and after counting on his fingers Bigtime figures out "That's one millimeter too many!" True to the trope, he takes the shell full-on and gets sent flying out of the Money Bin.

Space Goofs: In the episode "Bats in the Belfry", Candy gets brutally annoyed by bats because he thinks they are disgusting. The other aliens attempt to take the bats down, but end up failing. Finally, the bats shove underwear on Candy, causing him to reach his breaking point and chase them away; however, just as the other aliens are glad they are gone, Candy turns his face on them and chews them out, resulting in a Downer Ending.

In the VeggieTales episode Madame Blueberry, the titular character goes on a major shopping spree and has everything she purchases sent to her opulent treehouse mansion while she keeps shopping. Unbeknownst to her, the stuff she's buying is overloading the tree, causing her house to teeter closer and closer to destruction. Eventually she catches on and manages to stop the deliveries, just as the last item has fortuitously stabilized the house. And then, a butterfly lands on the roof, tipping the treehouse and making everything inside it fall into the nearby lake. Then the tree snaps back upright, catapulting her house off into the distance.

Rocky and Bullwinkle: Boris and Natasha overloaded the raft with supplies from Moosylvania. Fearless Leader shows up from his sub awarding Boris with a one ounce medal, enough to sink their raft.

In a song in the 3D children's cartoon WordWorld, Pig makes a pizza with toppings that all start with the letter P. He stacks the pizza up with "toppings" ranging from popcorn to pickles, creating a tower of various foods. Finally, he adds a single peanut, causing the entire tower to fall.

In an episode of Doug, Doug and Mr. Dink are aboard a fishing boat overloading with all sorts of mostly unnecessary equipment. Not until Mr. Dink needed the keys in which his wife tossed them to him was it enough to sink the boat with them on board.

In the episode "Put Your Head on My Shoulder", Amy takes Fry for a ride in her new car on Mercury. They proceed to run the fuel down by turning on all the appliances (including turning on the heater to counteract the air conditioning). The final straw is not when Fry puts Pop-Tarts™ in the toaster but rather when he turns up the darkness control on the toaster.

In "The Deep South", the video explaining how Atlanta ended up underwater shows that after it was relocated out in the Atlantic Ocean to draw more attention it was overcrowded with taller buildings, then finally tilted with the weight of a gold statue of Ted Turner.

The Angry Beavers: In one episode, a tree that has been growing since the time of the dinosaurs teeters on the edge of a cliff due to millions of years of erosion. Finally, a single fly lands on an exposed root-sending it toppling right into the protagonists' house.

American Dad! did a cliff-side variant in "Delorean Story-an". During a father and son road trip, Stan overinflated and burst his bubblegum at his face losing control and causing his car to nearly fall off a cliff. They manage to get out safely while the car is still in balance, until a Japanese motorist from an earlier encounter arrives and slightly adjusts their crooked side mirror causing the car to fall off the cliff.

A serious example in Gravity Falls episode "A Tale of Two Stans"; Stan was basically disowned by his family for accidentally ruining his genius brother's college admissions, and it's implied that this was only the latest incident Stan caused.

Stan's father: All you do is lie, cheat, and ride on your brother's coattails. Well, now you've cost this family potential millions.

True to its Looney Tunes origins, this trope shows up in Taz-Mania. In the first appearance of the Kiwi, Taz and Buddy Boar end up tied to a tree dangling over the edge of a cliff. The Kiwi returns Buddy's lucky coin, which it had stolen earlier, and the extra weight is enough to cause the tree to snap.

In "Pinkie Apple Pie", the Apple family and Pinkie Pie, sailing down a river in a makeshift boat weakly held together by vines and tree sap, fall over a waterfall. The boat manages to safely survive, and just as Granny Smith is amazed that the boat is still in one piece, Pinkie, held aloft by balloons, lands on the boat. Cue the boat splitting in two and sinking immediately.

In "Made in Manehattan", an old bench splits in two when Applejack puts her hat down on it. Later, an actress takes a single step on an old stage and it collapses.

In one episode of Back at the Barnyard the gang sets the Farmer up with a Gold Digger who wants to redecorate the barn and forces all the animals to relocate to an ad-hoc shack that can barely contain all of them. The shack explodes as soon as Pip (a mouse) squeezes himself in along with the rest of them.

In the Teen Titans Go! episode "Starliar", Starfire neglects to feed Silkie his pet food and he spends the rest of the episode eating everything in the tower. Near the end, he's experienced a Temporary Bulk Change and when he eats the unopened can of food he throws everything up.

In the Tom and Jerry cartoon "The Million Dollar Cat", Tom inherits a fortune, On One Condition — if he hurts another living thing, even a mouse, he loses the money. Jerry, naturally, takes advantage of this, continually following Tom around, despite the cat's best attempts to get rid of him and basically acting like a freeloader who ruins Tom's life. The final straw comes when he eats Tom's breakfast and attacks Tom with the rest of the breakfast material, which causes Tom to lose his temper, shreds the will, and attack Jerry.

Tom: Gee! I'm throwing away a million dollars... but I'm HAPPY!!!

In Not Without My Handbag, the girl defeats Satan (possessing the handbag) by giving him all the cakes in a bakery. He eats most of them and grows to an enormous size before she offers him one last chocolate éclair. He tries to refuse, but ends up eating it anyway. The monstrosity explodes, sending Satan back to hell and the inanimate handbag back to the girl's dead aunt.

On an episode of The Oblongs the teens are driven off the road by the two nasty Hill kids. It teeters on edge but, with a sigh of relief, it rights itself. Then the nasty kids drive up and kick their car off the cliff.

In A Flintstone Christmas, Fred insists on putting an ornament on the left side of his Christmas tree instead of on the right, despite Barney's warning, which causes the tree to double over and fall on top of him.

In the SpongeBob SquarePants episode "Shuffleboarding", SpongeBob and Patrick take Mermaid Man and Barnacle Boy's places at a shuffleboarding tournament and later start arresting everyone in Bikini Bottom for random Felony Misdemeanors, causing the jail to expand in size. When they arrest Man Ray and an old woman he was talking to at the laundromat, the jail explodes.

A riddle features a clever aversion of this. Suppose a truck weighing one tonne at the start of its journey (including the driver) is driving across a bridge with a weight limit of exactly one tonne. Halfway across the bridge, a robin weighing 75 grams lands on the bridge. What happens? Nothing: the truck now weighs less than a tonne, as it has burnt up some of the fuel which makes up some of its mass.

Other riddles play it straight. One man weighing 248 pounds is carrying three 1-pound coconuts, and needs to cross a bridge with a weight limit of 250 pounds. How does he do it? He juggles. Though this riddle is a case of Artistic License - Physics since throwing up a coconut results in additional downward force first when he tosses it (Newton's third law), and again when it hits his hand. Indeed, a similar riddle involving "birds in a truck" was busted by the MythBusters because of the downward force added by the birds' flight.

While the weight limit is usually a catch-all, it's also possible to drive a vehicle that may weigh more than the weight limit if it has enough pressure distributed across the bridge (rather than at one point). For instance, there are tables that are claimed to be able to hold up a ton... if it's spread out across the table.

Can only work with supported bridges (but doesn't necessarily have to), if it's a hanging construction you have all the strain exerted length-wise.

If you supersaturate a solution—dissolve something into a solvent (e.g. water) so that there is more of the solute (e.g. sugar) present than there could be under normal conditions—adding the tiniest amount of the solute into the apparently clear liquid will cause it to crystallize, as the added crystal provides a seed for the excess solute to grow upon. This is beyond annoying, among other things, when you are trying to make toffee.

Useful, though, in chemical heat packs. Just snap the enclosed metal disc inside out, the mechanical shock seeds crystallization, and the pack releases the stored heat of the solution.

To those more chemistry-savvy, the action described above is referred to as "falling out."

Analogously, homogeneous fluids in clean, smooth containers can under some circumstances be heated beyond their normal boiling point without boiling. Disturbing the fluid sufficiently, or introducing nucleation points, can then cause flash-boiling and potentially a small steam explosion.

Also, changing its pressure can cause it to boil. This, combined with the fact that evaporating liquids absorb heat, is very useful for refrigeration.

This was shown on MythBusters, and also Good Eats. It happens most often in everyday life when someone tries to boil purified water, usually in a microwave, which will explode if you put anything into it. To prevent this from happening, place a wooden spoon into the water (and use a container with a wide opening at the top).

Equivalent to the superheating described above, you can also supercool a fluid below the freezing point in a clean, smooth, container. Adding a nucleation site (or even just jolting the container) can cause it to instantly freeze.

Also examined on MythBusters, by supercooling beer and then rapping the bottle on a solid surface to cause it to freeze.

The Trope Namer is the proverbial "straw that broke the camel's back". This refers to a folk-tale that was persistent in both the Middle East and North Africa. According to the tale a camel could only carry XX kilogramsnote Of course, back then they didn't use kilograms; they used imperial cubit ells or something of supplies, and anything more would be too much. While the story is obviously not 100% true, like many folk-tales, it has a grain of truth to it. Apparently, caravan drivers were able to figure out close to the max weight that a camel could conceivably carry.

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